THE ICE CHEST I71 



milk that has been kept more than three or four days in 

 such a refrigerator, even though it is still perfectly sweet 

 and shows no signs of decomposition. 



In a well-constructed mechanical refrigerator the tem- 

 perature should not be over 40° anywhere. At such tem- 

 peratures most bacteria, if they grow at all, grow very 

 slowly; and kinds of food less subject to rapid decom- 

 position than milk (such as meat, vegetables, fruits, and 

 preserves) may be kept for a long time — as long as the 

 housekeeper ordinarily needs to preserve them. The atmos- 

 phere in a mechanical refrigerator is usually rather dry, 

 and vegetables are likely to wilt ; so it is generally recom- 

 mended that they be kept in a tight container. Practically 

 all other kinds of food keep better than on ice. 



3. Temperature of an Ice Chest. A far less efficient 

 means of obtaining low temperature is by the use of the 

 ordinary, ice chest — less efficient simply because the tem- 

 perature is higher. The temperature of ice chests is vari- 

 able, depending upon the size of the chest and the amount 

 of ice in it. It will sometimes be as low as 40°, or even 

 lower, but never quite reaches the freezing point ; at other 

 times it will run up to 50°, and as the ice melts, the tem- 

 perature rises to that of the outer air. Food preserved in 

 an icef chest is far less thoroughly protected than in cold- 

 storage plants. The use of the ice chest is simply a means 

 of checking the development of bacteria, but it by no 

 means stops their growth. Food may be preserved for quite 

 a while, although it is sure in the end to undergo certain 

 forms of putrefaction. 



The type of putrefaction that occurs in material kept 

 in an ice chest is usually somewhat different from that 



